A service-oriented architecture (SOA) is a software architecture where functionality is grouped around processes and packaged as interoperable services. The aim of a SOA is to reduce the coupling of services with operating systems, programming languages, and other technologies that underlie applications. A SOA separates functions into distinct units, or services, which are made accessible over a network. These services communicate with each other by passing data from one service to another, or by coordinating an activity between two or more services.
In a SOA, it is important to know which services are available at a given time. Conventional solutions for service availability use a static approach. For example, in Microsoft Windows, an appropriate service can be chosen out from a static registry entry in the operating system registry (based on a static GUID) or based on dynamic monikers that depends on static GUIDs.
Today, the static registration of services and interfaces is done during installation. Distributed applications are difficult to maintain due to network security issues. For example, DCOM security settings may change in every service pack or may vary from operating systems to operating system (e.g., from Microsoft Windows XP to Vista).